Determination of gap acceptance at priority intersections

Abstract

Vehicles from minor approach at Two Way Stop Controlled (TWSC) will wait for an appropriate gap to exist in the conflicting traffic stream before performing the merging or crossing manoeuvres at the intersection. In practice, driver's gap acceptance behaviour is one of the important aspects considered in the design and analysis of stop- controlled intersections. This paper describes the result of a study carried out to determine the drivers' gap acceptance at TWSC intersections where the major approach vehicles have priority over the minor road drivers. The data were collected at two TWSC intersections in an urban area using a video camera recording technique and gap data was analysed using the Maximum Likelihood method. The result of the study indicates that the critical gap for the drivers making the left-turn from minor road into the major was in the range of 5.00 to 10.00 seconds. The critical gap for the drivers making a right-turn from minor road into the major was in the range of 10.00 to 15.00 seconds. The result also shows that the gap acceptance values decrease when the volume of the major stream traffic increases.